Implement CFI type checks for non-virtual calls.

This uses the same class metadata currently used for virtual call and
cast checks.

The new flag is -fsanitize=cfi-nvcall. For consistency, the -fsanitize=cfi-vptr
flag has been renamed -fsanitize=cfi-vcall.

Differential Revision: http://reviews.llvm.org/D8756

llvm-svn: 233874

diff --git a/clang/docs/ControlFlowIntegrity.rst b/clang/docs/ControlFlowIntegrity.rst
index 51c9917..915385b 100644 (file)
--- a/clang/docs/ControlFlowIntegrity.rst
+++ b/clang/docs/ControlFlowIntegrity.rst
@@ -27,8 +27,8 @@ the program must be structured such that certain object files are compiled
 with CFI enabled, and are statically linked into the program. This may
 preclude the use of shared libraries in some cases.
 
-Clang currently implements forward-edge CFI for virtual calls. More schemes
-are under development.
+Clang currently implements forward-edge CFI for member function calls and
+bad cast checking. More schemes are under development.
 
 .. _gold plugin: http://llvm.org/docs/GoldPlugin.html
 
@@ -38,11 +38,11 @@ Forward-Edge CFI for Virtual Calls
 This scheme checks that virtual calls take place using a vptr of the correct
 dynamic type; that is, the dynamic type of the called object must be a
 derived class of the static type of the object used to make the call.
-This CFI scheme can be enabled on its own using ``-fsanitize=cfi-vptr``.
+This CFI scheme can be enabled on its own using ``-fsanitize=cfi-vcall``.
 
 For this scheme to work, all translation units containing the definition
 of a virtual member function (whether inline or not) must be compiled
-with ``-fsanitize=cfi-vptr`` enabled and be statically linked into the
+with ``-fsanitize=cfi-vcall`` enabled and be statically linked into the
 program. Classes in the C++ standard library (under namespace ``std``) are
 exempted from checking, and therefore programs may be linked against a
 pre-built standard library, but this may change in the future.
@@ -95,6 +95,23 @@ and be statically linked into the program. Classes in the C++ standard library
 may be linked against a pre-built standard library, but this may change in
 the future.
 
+Non-Virtual Member Function Call Checking
+-----------------------------------------
+
+This scheme checks that non-virtual calls take place using an object of
+the correct dynamic type; that is, the dynamic type of the called object
+must be a derived class of the static type of the object used to make the
+call. The checks are currently only introduced where the object is of a
+polymorphic class type.  This CFI scheme can be enabled on its own using
+``-fsanitize=cfi-nvcall``.
+
+For this scheme to work, all translation units containing the definition
+of a virtual member function (whether inline or not) must be compiled
+with ``-fsanitize=cfi-nvcall`` enabled and be statically linked into the
+program. Classes in the C++ standard library (under namespace ``std``) are
+exempted from checking, and therefore programs may be linked against a
+pre-built standard library, but this may change in the future.
+
 .. _cfi-strictness:
 
 Strictness

diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index 29c4d4e..bf8ce78 100644 (file)
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -974,7 +974,9 @@ are listed below.
       dynamic type. Implies ``-flto``.
    -  ``-fsanitize=cfi-unrelated-cast``: Cast from ``void*`` or another
       unrelated type to the wrong dynamic type. Implies ``-flto``.
-   -  ``-fsanitize=cfi-vptr``: Use of an object whose vptr is of the
+   -  ``-fsanitize=cfi-nvcall``: Non-virtual call via an object whose vptr is of
+      the wrong dynamic type. Implies ``-flto``.
+   -  ``-fsanitize=cfi-vcall``: Virtual call via an object whose vptr is of the
       wrong dynamic type. Implies ``-flto``.
    -  ``-fsanitize=enum``: Load of a value of an enumerated type which
       is not in the range of representable values for that enumerated

diff --git a/clang/include/clang/Basic/Sanitizers.def b/clang/include/clang/Basic/Sanitizers.def
index fa58a34..65ababd 100644 (file)
--- a/clang/include/clang/Basic/Sanitizers.def
+++ b/clang/include/clang/Basic/Sanitizers.def
@@ -82,8 +82,10 @@ SANITIZER("dataflow", DataFlow)
 SANITIZER("cfi-cast-strict", CFICastStrict)
 SANITIZER("cfi-derived-cast", CFIDerivedCast)
 SANITIZER("cfi-unrelated-cast", CFIUnrelatedCast)
-SANITIZER("cfi-vptr", CFIVptr)
-SANITIZER_GROUP("cfi", CFI, CFIDerivedCast | CFIUnrelatedCast | CFIVptr)
+SANITIZER("cfi-nvcall", CFINVCall)
+SANITIZER("cfi-vcall", CFIVCall)
+SANITIZER_GROUP("cfi", CFI,
+                CFIDerivedCast | CFIUnrelatedCast | CFINVCall | CFIVCall)
 
 // -fsanitize=undefined-trap includes sanitizers from -fsanitize=undefined
 // that can be used without runtime support, generally by providing extra

diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index 84d6437..bd15c12 100644 (file)
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -2088,14 +2088,6 @@ llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
   return VTable;
 }
 
-void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXMethodDecl *MD,
-                                                llvm::Value *VTable) {
-  if (!SanOpts.has(SanitizerKind::CFIVptr))
-    return;
-
-  EmitVTablePtrCheck(MD->getParent(), VTable);
-}
-
 // If a class has a single non-virtual base and does not introduce or override
 // virtual member functions or fields, it will have the same layout as its base.
 // This function returns the least derived such class.
@@ -2131,6 +2123,15 @@ LeastDerivedClassWithSameLayout(const CXXRecordDecl *RD) {
       RD->bases_begin()->getType()->getAsCXXRecordDecl());
 }
 
+void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXMethodDecl *MD,
+                                                llvm::Value *VTable) {
+  const CXXRecordDecl *ClassDecl = MD->getParent();
+  if (!SanOpts.has(SanitizerKind::CFICastStrict))
+    ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl);
+
+  EmitVTablePtrCheck(ClassDecl, VTable);
+}
+
 void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T,
                                                 llvm::Value *Derived,
                                                 bool MayBeNull) {

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 6852d3a..f7bf406 100644 (file)
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -256,6 +256,12 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
   } else if (UseVirtualCall) {
     Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty);
   } else {
+    if (SanOpts.has(SanitizerKind::CFINVCall) &&
+        MD->getParent()->isDynamicClass()) {
+      llvm::Value *VTable = GetVTablePtr(This, Int8PtrTy);
+      EmitVTablePtrCheckForCall(MD, VTable);
+    }
+
     if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
       Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
     else if (!DevirtualizedMethod)

diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 372db7a..57370a6 100644 (file)
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -842,7 +842,10 @@ void CodeGenModule::EmitDeferredVTables() {
 
 void CodeGenModule::EmitVTableBitSetEntries(llvm::GlobalVariable *VTable,
                                             const VTableLayout &VTLayout) {
-  if (!LangOpts.Sanitize.has(SanitizerKind::CFIVptr))
+  if (!LangOpts.Sanitize.has(SanitizerKind::CFIVCall) &&
+      !LangOpts.Sanitize.has(SanitizerKind::CFINVCall) &&
+      !LangOpts.Sanitize.has(SanitizerKind::CFIDerivedCast) &&
+      !LangOpts.Sanitize.has(SanitizerKind::CFIUnrelatedCast))
     return;
 
   llvm::Metadata *VTableMD = llvm::ConstantAsMetadata::get(VTable);

diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 62f1293..7bb0a9b 100644 (file)
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -1443,7 +1443,8 @@ llvm::Value *ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
   Ty = Ty->getPointerTo()->getPointerTo();
   llvm::Value *VTable = CGF.GetVTablePtr(This, Ty);
 
-  CGF.EmitVTablePtrCheckForCall(cast<CXXMethodDecl>(GD.getDecl()), VTable);
+  if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
+    CGF.EmitVTablePtrCheckForCall(cast<CXXMethodDecl>(GD.getDecl()), VTable);
 
   uint64_t VTableIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(GD);
   llvm::Value *VFuncPtr =

diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 88725cd..cd3785c 100644 (file)
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -48,7 +48,7 @@ enum SanitizeKind : uint64_t {
   RecoverableByDefault = Undefined | Integer,
   Unrecoverable = Address | Unreachable | Return,
   LegacyFsanitizeRecoverMask = Undefined | Integer,
-  NeedsLTO = CFIDerivedCast | CFIUnrelatedCast | CFIVptr,
+  NeedsLTO = CFI,
 };
 }
 

diff --git a/clang/test/CodeGenCXX/cfi-nvcall.cpp b/clang/test/CodeGenCXX/cfi-nvcall.cpp
new file mode 100644 (file)
index 0000000..b0db478
--- /dev/null
+++ b/clang/test/CodeGenCXX/cfi-nvcall.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-nvcall -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-nvcall,cfi-cast-strict -emit-llvm -o - %s | FileCheck --check-prefix=CHECK-STRICT %s
+
+struct A {
+  virtual void f();
+};
+
+struct B : A {
+  int i;
+  void g();
+};
+
+struct C : A {
+  void g();
+};
+
+// CHECK-LABEL: @bg
+// CHECK-STRICT-LABEL: @bg
+extern "C" void bg(B *b) {
+  // CHECK: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"1B")
+  // CHECK-STRICT: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"1B")
+  b->g();
+}
+
+// CHECK-LABEL: @cg
+// CHECK-STRICT-LABEL: @cg
+extern "C" void cg(C *c) {
+  // http://clang.llvm.org/docs/ControlFlowIntegrity.html#strictness
+  // In this case C's layout is the same as its base class, so we allow
+  // c to be of type A in non-strict mode.
+
+  // CHECK: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"1A")
+  // CHECK-STRICT: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"1C")
+  c->g();
+}

diff --git a/clang/test/CodeGenCXX/cfi-vptr.cpp b/clang/test/CodeGenCXX/cfi-vcall.cpp
similarity index 88%
rename from clang/test/CodeGenCXX/cfi-vptr.cpp
rename to clang/test/CodeGenCXX/cfi-vcall.cpp
index 545f22c..bfbbcea 100644 (file)
--- a/clang/test/CodeGenCXX/cfi-vptr.cpp
+++ b/clang/test/CodeGenCXX/cfi-vcall.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-vptr -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-vcall -emit-llvm -o - %s | FileCheck %s
 
 struct A {
   A();
@@ -49,7 +49,7 @@ void af(A *a) {
 
 // CHECK: define internal void @_Z2dfPN12_GLOBAL__N_11DE
 void df(D *d) {
-  // CHECK: {{%[^ ]*}} = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"[{{.*}}cfi-vptr.cpp]N12_GLOBAL__N_11DE")
+  // CHECK: {{%[^ ]*}} = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"[{{.*}}cfi-vcall.cpp]N12_GLOBAL__N_11DE")
   d->f();
 }
 
@@ -67,7 +67,7 @@ void foo() {
 // CHECK-DAG: !{!"1A", [10 x i8*]* @_ZTVN12_GLOBAL__N_11DE, i64 32}
 // CHECK-DAG: !{!"1B", [10 x i8*]* @_ZTVN12_GLOBAL__N_11DE, i64 32}
 // CHECK-DAG: !{!"1C", [10 x i8*]* @_ZTVN12_GLOBAL__N_11DE, i64 72}
-// CHECK-DAG: !{!"[{{.*}}cfi-vptr.cpp]N12_GLOBAL__N_11DE", [10 x i8*]* @_ZTVN12_GLOBAL__N_11DE, i64 32}
+// CHECK-DAG: !{!"[{{.*}}cfi-vcall.cpp]N12_GLOBAL__N_11DE", [10 x i8*]* @_ZTVN12_GLOBAL__N_11DE, i64 32}
 // CHECK-DAG: !{!"1A", [5 x i8*]* @_ZTV1B, i64 32}
 // CHECK-DAG: !{!"1B", [5 x i8*]* @_ZTV1B, i64 32}
 // CHECK-DAG: !{!"1A", [5 x i8*]* @_ZTV1C, i64 32}

diff --git a/clang/test/Driver/fsanitize.c b/clang/test/Driver/fsanitize.c
index f43029b..994b2b2 100644 (file)
--- a/clang/test/Driver/fsanitize.c
+++ b/clang/test/Driver/fsanitize.c
@@ -206,11 +206,13 @@
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-derived-cast -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-DCAST
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-unrelated-cast -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-UCAST
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vptr -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-VPTR
-// CHECK-CFI: -emit-llvm-bc{{.*}}-fsanitize=cfi-derived-cast,cfi-unrelated-cast,cfi-vptr
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-nvcall -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-NVCALL
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vcall -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-VCALL
+// CHECK-CFI: -emit-llvm-bc{{.*}}-fsanitize=cfi-derived-cast,cfi-unrelated-cast,cfi-nvcall,cfi-vcall
 // CHECK-CFI-DCAST: -emit-llvm-bc{{.*}}-fsanitize=cfi-derived-cast
 // CHECK-CFI-UCAST: -emit-llvm-bc{{.*}}-fsanitize=cfi-unrelated-cast
-// CHECK-CFI-VPTR: -emit-llvm-bc{{.*}}-fsanitize=cfi-vptr
+// CHECK-CFI-NVCALL: -emit-llvm-bc{{.*}}-fsanitize=cfi-nvcall
+// CHECK-CFI-VCALL: -emit-llvm-bc{{.*}}-fsanitize=cfi-vcall
 
 // RUN: %clang_cl -fsanitize=address -c -MDd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // RUN: %clang_cl -fsanitize=address -c -MTd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL